Effects of different kind of fructans on in vitro growth of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium lactis

The effects of fructans of Cichorium intybus, Helianthus tuberosus and Agave angustifolia spp. tequilana were evaluated on in vitro growth of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium lactis. Fructan concentrations were 0, 7, 14 or 21 g/L of man rogosa sharpe broth. The pH values and optic density at 600 nm (OD600) were measured. Broths were inoculated and incubated at 35 degrees C for 48 h. A complete randomized design was used with a 3 x 4 factorial arrangement of treatments: fructans (C. intybus, A. angustifolia spp. tequilana, H. tuberosus) and doses (0, 7, 14 or 21 g/L). For all bacteria, pH values quadratically decreased as fructan doses increased. Contrarily, OD600 values quadratically increased as fructan doses rose. In L. acidophilus, the pH values of the medium with fructans from C. intybus and H. tuberosus were lower and OD600 values were higher than with A. angustifolia spp. tequilana fructans. In L. casei pH and OD600 values were similar for all fructan sources. In B. lactis, H. tuberosus fructans induced lower pH and higher OD600 values than C. intybus and A. angustifolia spp. tequilana fructans. Results indicated that fructans from A. angustifolia spp. tequilana, C. intybus and H. tuberosus increased growth of B. lactis, L. casei and L. acidophilus. Although bacteria had different affinities for fructans, the lowest polymerization value improved bacterial growth.